Conventionally, in an electric vacuum cleaner, configurations have been proposed in which a collected-dust-amount indicating device is disposed therein for notifying a user of a timing of replacing its paper bag (see Patent Literature 1, for example). FIG. 6 is a perspective view of a vacuum cleaner body having a conventional collected-dust-amount indicating device. FIG. 7 is a cross-sectional view of the vacuum cleaner body, taken along line 7-7 of FIG. 6. As shown in FIGS. 6 and 7, in the conventional electric vacuum cleaner, electric vacuum cleaner body 121 includes motor 122 and dust collection chamber 124 in which paper bag 123 is attached. Moreover, the conventional electric vacuum cleaner includes lid 125 that covers an upper opening of dust collection chamber 124.
In lid 125, inclined surface 129 is formed that inclines downward from a horizontal surface. In inclined surface 129, suction port 130 is disposed. A hose (not shown) is coupled detachably with electric vacuum cleaner body 121 via suction port 130. In addition, in a vicinity of suction port 130 in the inside of lid 125, transparent pipe 133 and indicator elbow 134 are attached. Transparent pipe 133 accommodates coil spring 135, tube body 136, and cap 137. Transparent pipe 133 communicates with dust collection chamber 124 via indicator elbow 134. An indicator (collected-dust-amount indicating device 16) is configured with transparent pipe 133 and indicator elbow 134.
With the above configuration, pressure in dust collection chamber 124 decreases as paper bag 123 accumulates dust. Tube body 136 moves in accordance with a relation of the elastic force of coil spring 135 to a difference in pressure between the atmospheric pressure and the pressure in the inside of dust collection chamber 124. Then, tube body 136 moves to reach the position of window 138 disposed in inclined surface 129 of lid 125, which can notify the user of the timing of replacing paper bag 123.
In conventional electric vacuum cleaners, since no examination has been made of component commonality of collected-dust-amount indicating devices among different types of vacuum cleaners, there may be a problem of higher manufacturing costs of the electric vacuum cleaners.
That is, there is the need for customizing each of the designs of the collected-dust-amount indicating devices, depending on a dust collecting system of the electric vacuum cleaner, an appearance configuration of the electric vacuum cleaner body, an arrangement position of the device, and the like. For this reason, manufacturing costs of the electric vacuum cleaners may increase.
In addition, there is the need for preparing customized metal molds of each of the collected-dust-amount indicating devices, with the each having a customized design depending on the dust collecting system of the cleaner, the appearance configuration of the cleaner body, the arrangement position of the device, and the like. This may result in increased manufacturing costs of the electric vacuum cleaners.    Patent Literature 1: Japanese Patent Unexamined Publication No. H01-277526